But here goes. I have ordered my play off final ticket online + 1 for brother in law but did not reasign the brother in laws ticket so both tickets have been ordered in my name. Will that be a problem getting him in the stadium?
No, based on previous Wembley Ticketmaster experience for NFL games. Each ticket is designed to be used on a phone, most likely within the Ticketmaster app, and the confirmation email usually gives instructions for how to distribute these. Ultimately, it's a QR code you scan at the turnstiles, so no ID issues on entry.